1. Field of the Invention
The present invention relates to an image display method and an image display system that display images by projection light used for displaying images.
2. Description of the Related Art
In recent years, image display systems that include a projector and a screen (image display screens) have often been used for presentations, for watching movies in the home, and the like. In such image display systems, the screens used with the projectors can be normally classified into two types, reflective screens and transmissive screens. With a reflective screen, the projection light that is projected by a projector is reflected and diffused on the incident side, so that a visible image can be displayed from the display side (the incident side for the projection light). On the other hand, with a transmissive screen, the projection light is transmitted and diffused in the direction in which the projection light is incident, so that a visible image can be displayed from a back surface (one example of such is the transmissive screen disclosed by Japanese Laid-Open Patent Publication No. 2001-242546.
Printed materials such as posters are often attached to a show window in a store or the like to inform customers of a sale or event and so encourage customers to make purchases. However, with this kind of promotional means, only an ordinary static display is possible, which makes it difficult to attract customers' attention to such promotional means. As a result, there has been the problem that it has not been possible to sufficiently inform customers of a sale or other event. Further problems are caused by the cost of producing posters and the need to manually replace such posters whenever there is a sale or event. As one solution, image display systems constructed of a transmissive screen and a projector have started to be introduced in recent years. With such an image display system, the transmissive screen is attached to a show window or the like and projection light for displaying images is projected onto the screen from the projector that has been set up inside the store. By doing so, it is possible to display moving images that promote a sale or an event and can be viewed from outside the show window. Accordingly, with this image display system, since the displaying of moving images in a show window (specifically on a transmissive screen attached to a show window) is itself novel, it is possible to attract customers' attention to the moving images, resulting in the customers being sufficiently informed of sales and other events. It is also possible to produce advertising images at a low cost using a personal computer, for example, and the need to manually change posters and the like can be avoided.
However, conventional image display systems that are used for advertising purposes have the following problem. When images are displayed on a screen that has been attached to a show window, the projector of the image display system has to be set up inside the store, so that it is possible to view the images only from outside the show window, that is, from outside the store. This means that with this image display system, there is the problem that the system does not have any advertising effect on customers inside the store. It would be conceivable to use a method where the advertising effect is improved by attaching a reflective screen to a show window or the like separately to the transmissive screen so that images can be displayed separately to the customers inside the store. However, since it would be necessary to use two costly projectors, this method is difficult to implement due to the high cost involved.